Advanced Process and Chemical Complex Analysis Systems
Transcript of Advanced Process and Chemical Complex Analysis Systems
157g
Advanced Process and Chemical Complex Analysis Systems
Derya Ozyurtb Aimin Xub Thomas A Hertwiga Janardhana R Punurub Ralph W Pikeb F Carl Knopfb Jack R Hopperc and Carl L Yawsc
a IMC Phospates Uncle Sam LA 70792 tahertwigimcglobalcom b Louisiana State University Louisiana State University ozyurtlsuedu pikechelsuedu
axu1lsuedu knopfchelsuedu j_punuruyahoocom c Lamar University Beaumont TX 77710 hopperjrhallamaredu yawsclhallamaredu
Key words Energy Conservation Pollution Prevention Sustainability Chemical Complex
Prepared for presentation at the 2002 Annual Meeting Indianapolis IN November 3-8
Copyright copy Louisiana State University 2002
AIChE shall not be responsible for statements or opinions contained in papers or printed in its publications
Abstract
The Advanced Process Analysis System is used to perform economic and environmental
evaluations of a plant The main components of this system are a flowsheeting program an on-line
optimization program a chemical reactor analysis program a heat exchanger network design
program and a pollution assessment module A Windows interface has been used to integrate these
programs into one user-friendly application An accurate description of the process is obtained from
process flowsheeting and on-line optimization Then an evaluation of the best types of chemical
reactors is performed to modify and improve the process and pinch analysis is used to determine
the best configuration for the heat exchanger network and determine the minimum utilities needed
for the process The pollution index evaluation is used to identify and minimize emissions A tutorial
has two plant simulations and two actual plants
The Chemical Complex Analysis System incorporates economic environmental and
sustainable costs and solves a MINLP for the best configuration of plants in a chemical production
complex The system incorporates a flowsheeting component where the simulations of the plants
in the complex are entered through windows and stored in the database to be shared with the other
components of the system Also entered are prices and economic environmental and sustainable
costs Then the optimum configuration of plants in the complex is determined and the results are
presented to the user on the flowsheet and in tables from the GAMS solution of the MINLP The
tutorial has a complex simulation and an actual agricultural chemical complex
These programs and users manual with tutorials can be obtained from the LSU Minerals
Processing Research Institutes web site wwwmprilsuedu at no charge
ADVANCED PROCESS ANALYSIS SYSTEM
This advanced process analysis methodology is based on the framework shown in Figure 1
and structure shown in Figure 2 On-line optimization and data from the plants distributed control
system ensure these analyses match the performance of the actual plant and provide set-points for
the distributed control system for the optimal operating conditions for the plant Then the System
is used for evaluating the best types and configuration of chemical reactors and separation units
using the chemical reactor analysis flowsheeting and pinch analysis programs Also processing
options ie changes in chemistry chemical reactor configurations solvents and associated optimal
operating conditions for source reduction or recycling of identified pollutants can be determined
An interactive Windows program integrates the programs as outlined in Figure 2 to analyze
source reduction recycle and retrofit It integrated process economic and environmental data which
are shared by chemical reactor analysis process flowsheeting pinch analysis and on-line
optimization programs The chemical reactor analysis program (Saleh Hopper and Walker 1995)
determines the best chemical
reactor type and operating
conditions The flowsheeting
program FlowSim integrates the
chemical reactor with the feed
preparation and product
purification facili t ies as
illustrated in Figure 1 The pinch
analysis program THEN (Knopf
Figure 1 Advanced Process Analysis System Framework
1
1993) integrate the networks
of heat exchangers boilers
condensers and furnaces for
best energy utilization The
on-line optimization program
(Chen et al 1998) provides
accurate plant data to validate
the plant descriptions by the
chemical reactor analysis
flowsheeting and pinch
analysis programs Also the pollution index program is used to minimizes waste generation based
on pollution balances and pollution indices
The System has been applied to actual plants including the alkylation plant at the Motiva
refinery in Convent Louisiana and sulfuric acid contact plant at IMC Agricorsquos agricultural
chemicals complex in Uncle Sam Louisiana Detailed plant descriptions of the refinery alkylation
process and the contact sulfuric acid process were used with the System in collaboration with the
process engineers from these companies This ensured that the programs work on actual plants and
meet the needs and requirements of the process and design engineers
On-Line Optimization On-line optimization is the use of an automated system which
adjusts the operation of a plant based on product scheduling and production control to maximize
profit and minimize emissions by providing set points to the distributed control system The plant
model has to describe the current performance of the plant and plant data are sampled from the
2
distributed control system for this purpose This data is used to update and adjust parameters in the
plant model to eliminate any plant and model mismatch Before this can be done the sampled data
has to be processed through gross error detection procedures to eliminate erroneous information that
could come from sources such as a broken instrument Then it is processed through data
reconciliation procedures to adjust it for consistency with material and energy balances This
reconciled data is precise and consistent data which is used to update the plant model parameters to
ensure the plant model accurately predicts the performance of the plant The parameters of the
economics model are updated also and these include sales prices and demand for products and costs
and availability of raw materials Typically the optimization cycle is repeated every three to twelve
hours and this interval depends on the settling time of the plant
Chemical Reactor Analysis A comprehensive interactive computer simulation for three-
phase catalatic gas-liquid reactors and subsets of these reactors which has a wide range of
applications such as oxidation hydrogenation hydrodesulfurization hydrocracking and Fischer-
Tropsch synthesis (Saleh Hopper and Walker 1995) The program interactively guides the engineer
to select the best reactor design for the reacting system based on the characteristics of ten different
types of industrial catalytic gas-liquid reactors which includes catalyst particle diameter and loading
diffusivities flow regimes gas-liquid and liquid-solid mass transfer rates gas and liquid dispersions
heat transfer holdup among others The program solves the conservation equations and it has
checks for the validity of the design eg not allowing a complete catalyst wetting factor if the liquid
flow rate is not sufficient
Pinch Analysis Pinch technology determines the minimum utilities for heat exchanger
networks It employs three concepts the composite curves the grid diagram of process streams and
3
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
Abstract
The Advanced Process Analysis System is used to perform economic and environmental
evaluations of a plant The main components of this system are a flowsheeting program an on-line
optimization program a chemical reactor analysis program a heat exchanger network design
program and a pollution assessment module A Windows interface has been used to integrate these
programs into one user-friendly application An accurate description of the process is obtained from
process flowsheeting and on-line optimization Then an evaluation of the best types of chemical
reactors is performed to modify and improve the process and pinch analysis is used to determine
the best configuration for the heat exchanger network and determine the minimum utilities needed
for the process The pollution index evaluation is used to identify and minimize emissions A tutorial
has two plant simulations and two actual plants
The Chemical Complex Analysis System incorporates economic environmental and
sustainable costs and solves a MINLP for the best configuration of plants in a chemical production
complex The system incorporates a flowsheeting component where the simulations of the plants
in the complex are entered through windows and stored in the database to be shared with the other
components of the system Also entered are prices and economic environmental and sustainable
costs Then the optimum configuration of plants in the complex is determined and the results are
presented to the user on the flowsheet and in tables from the GAMS solution of the MINLP The
tutorial has a complex simulation and an actual agricultural chemical complex
These programs and users manual with tutorials can be obtained from the LSU Minerals
Processing Research Institutes web site wwwmprilsuedu at no charge
ADVANCED PROCESS ANALYSIS SYSTEM
This advanced process analysis methodology is based on the framework shown in Figure 1
and structure shown in Figure 2 On-line optimization and data from the plants distributed control
system ensure these analyses match the performance of the actual plant and provide set-points for
the distributed control system for the optimal operating conditions for the plant Then the System
is used for evaluating the best types and configuration of chemical reactors and separation units
using the chemical reactor analysis flowsheeting and pinch analysis programs Also processing
options ie changes in chemistry chemical reactor configurations solvents and associated optimal
operating conditions for source reduction or recycling of identified pollutants can be determined
An interactive Windows program integrates the programs as outlined in Figure 2 to analyze
source reduction recycle and retrofit It integrated process economic and environmental data which
are shared by chemical reactor analysis process flowsheeting pinch analysis and on-line
optimization programs The chemical reactor analysis program (Saleh Hopper and Walker 1995)
determines the best chemical
reactor type and operating
conditions The flowsheeting
program FlowSim integrates the
chemical reactor with the feed
preparation and product
purification facili t ies as
illustrated in Figure 1 The pinch
analysis program THEN (Knopf
Figure 1 Advanced Process Analysis System Framework
1
1993) integrate the networks
of heat exchangers boilers
condensers and furnaces for
best energy utilization The
on-line optimization program
(Chen et al 1998) provides
accurate plant data to validate
the plant descriptions by the
chemical reactor analysis
flowsheeting and pinch
analysis programs Also the pollution index program is used to minimizes waste generation based
on pollution balances and pollution indices
The System has been applied to actual plants including the alkylation plant at the Motiva
refinery in Convent Louisiana and sulfuric acid contact plant at IMC Agricorsquos agricultural
chemicals complex in Uncle Sam Louisiana Detailed plant descriptions of the refinery alkylation
process and the contact sulfuric acid process were used with the System in collaboration with the
process engineers from these companies This ensured that the programs work on actual plants and
meet the needs and requirements of the process and design engineers
On-Line Optimization On-line optimization is the use of an automated system which
adjusts the operation of a plant based on product scheduling and production control to maximize
profit and minimize emissions by providing set points to the distributed control system The plant
model has to describe the current performance of the plant and plant data are sampled from the
2
distributed control system for this purpose This data is used to update and adjust parameters in the
plant model to eliminate any plant and model mismatch Before this can be done the sampled data
has to be processed through gross error detection procedures to eliminate erroneous information that
could come from sources such as a broken instrument Then it is processed through data
reconciliation procedures to adjust it for consistency with material and energy balances This
reconciled data is precise and consistent data which is used to update the plant model parameters to
ensure the plant model accurately predicts the performance of the plant The parameters of the
economics model are updated also and these include sales prices and demand for products and costs
and availability of raw materials Typically the optimization cycle is repeated every three to twelve
hours and this interval depends on the settling time of the plant
Chemical Reactor Analysis A comprehensive interactive computer simulation for three-
phase catalatic gas-liquid reactors and subsets of these reactors which has a wide range of
applications such as oxidation hydrogenation hydrodesulfurization hydrocracking and Fischer-
Tropsch synthesis (Saleh Hopper and Walker 1995) The program interactively guides the engineer
to select the best reactor design for the reacting system based on the characteristics of ten different
types of industrial catalytic gas-liquid reactors which includes catalyst particle diameter and loading
diffusivities flow regimes gas-liquid and liquid-solid mass transfer rates gas and liquid dispersions
heat transfer holdup among others The program solves the conservation equations and it has
checks for the validity of the design eg not allowing a complete catalyst wetting factor if the liquid
flow rate is not sufficient
Pinch Analysis Pinch technology determines the minimum utilities for heat exchanger
networks It employs three concepts the composite curves the grid diagram of process streams and
3
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
ADVANCED PROCESS ANALYSIS SYSTEM
This advanced process analysis methodology is based on the framework shown in Figure 1
and structure shown in Figure 2 On-line optimization and data from the plants distributed control
system ensure these analyses match the performance of the actual plant and provide set-points for
the distributed control system for the optimal operating conditions for the plant Then the System
is used for evaluating the best types and configuration of chemical reactors and separation units
using the chemical reactor analysis flowsheeting and pinch analysis programs Also processing
options ie changes in chemistry chemical reactor configurations solvents and associated optimal
operating conditions for source reduction or recycling of identified pollutants can be determined
An interactive Windows program integrates the programs as outlined in Figure 2 to analyze
source reduction recycle and retrofit It integrated process economic and environmental data which
are shared by chemical reactor analysis process flowsheeting pinch analysis and on-line
optimization programs The chemical reactor analysis program (Saleh Hopper and Walker 1995)
determines the best chemical
reactor type and operating
conditions The flowsheeting
program FlowSim integrates the
chemical reactor with the feed
preparation and product
purification facili t ies as
illustrated in Figure 1 The pinch
analysis program THEN (Knopf
Figure 1 Advanced Process Analysis System Framework
1
1993) integrate the networks
of heat exchangers boilers
condensers and furnaces for
best energy utilization The
on-line optimization program
(Chen et al 1998) provides
accurate plant data to validate
the plant descriptions by the
chemical reactor analysis
flowsheeting and pinch
analysis programs Also the pollution index program is used to minimizes waste generation based
on pollution balances and pollution indices
The System has been applied to actual plants including the alkylation plant at the Motiva
refinery in Convent Louisiana and sulfuric acid contact plant at IMC Agricorsquos agricultural
chemicals complex in Uncle Sam Louisiana Detailed plant descriptions of the refinery alkylation
process and the contact sulfuric acid process were used with the System in collaboration with the
process engineers from these companies This ensured that the programs work on actual plants and
meet the needs and requirements of the process and design engineers
On-Line Optimization On-line optimization is the use of an automated system which
adjusts the operation of a plant based on product scheduling and production control to maximize
profit and minimize emissions by providing set points to the distributed control system The plant
model has to describe the current performance of the plant and plant data are sampled from the
2
distributed control system for this purpose This data is used to update and adjust parameters in the
plant model to eliminate any plant and model mismatch Before this can be done the sampled data
has to be processed through gross error detection procedures to eliminate erroneous information that
could come from sources such as a broken instrument Then it is processed through data
reconciliation procedures to adjust it for consistency with material and energy balances This
reconciled data is precise and consistent data which is used to update the plant model parameters to
ensure the plant model accurately predicts the performance of the plant The parameters of the
economics model are updated also and these include sales prices and demand for products and costs
and availability of raw materials Typically the optimization cycle is repeated every three to twelve
hours and this interval depends on the settling time of the plant
Chemical Reactor Analysis A comprehensive interactive computer simulation for three-
phase catalatic gas-liquid reactors and subsets of these reactors which has a wide range of
applications such as oxidation hydrogenation hydrodesulfurization hydrocracking and Fischer-
Tropsch synthesis (Saleh Hopper and Walker 1995) The program interactively guides the engineer
to select the best reactor design for the reacting system based on the characteristics of ten different
types of industrial catalytic gas-liquid reactors which includes catalyst particle diameter and loading
diffusivities flow regimes gas-liquid and liquid-solid mass transfer rates gas and liquid dispersions
heat transfer holdup among others The program solves the conservation equations and it has
checks for the validity of the design eg not allowing a complete catalyst wetting factor if the liquid
flow rate is not sufficient
Pinch Analysis Pinch technology determines the minimum utilities for heat exchanger
networks It employs three concepts the composite curves the grid diagram of process streams and
3
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
1993) integrate the networks
of heat exchangers boilers
condensers and furnaces for
best energy utilization The
on-line optimization program
(Chen et al 1998) provides
accurate plant data to validate
the plant descriptions by the
chemical reactor analysis
flowsheeting and pinch
analysis programs Also the pollution index program is used to minimizes waste generation based
on pollution balances and pollution indices
The System has been applied to actual plants including the alkylation plant at the Motiva
refinery in Convent Louisiana and sulfuric acid contact plant at IMC Agricorsquos agricultural
chemicals complex in Uncle Sam Louisiana Detailed plant descriptions of the refinery alkylation
process and the contact sulfuric acid process were used with the System in collaboration with the
process engineers from these companies This ensured that the programs work on actual plants and
meet the needs and requirements of the process and design engineers
On-Line Optimization On-line optimization is the use of an automated system which
adjusts the operation of a plant based on product scheduling and production control to maximize
profit and minimize emissions by providing set points to the distributed control system The plant
model has to describe the current performance of the plant and plant data are sampled from the
2
distributed control system for this purpose This data is used to update and adjust parameters in the
plant model to eliminate any plant and model mismatch Before this can be done the sampled data
has to be processed through gross error detection procedures to eliminate erroneous information that
could come from sources such as a broken instrument Then it is processed through data
reconciliation procedures to adjust it for consistency with material and energy balances This
reconciled data is precise and consistent data which is used to update the plant model parameters to
ensure the plant model accurately predicts the performance of the plant The parameters of the
economics model are updated also and these include sales prices and demand for products and costs
and availability of raw materials Typically the optimization cycle is repeated every three to twelve
hours and this interval depends on the settling time of the plant
Chemical Reactor Analysis A comprehensive interactive computer simulation for three-
phase catalatic gas-liquid reactors and subsets of these reactors which has a wide range of
applications such as oxidation hydrogenation hydrodesulfurization hydrocracking and Fischer-
Tropsch synthesis (Saleh Hopper and Walker 1995) The program interactively guides the engineer
to select the best reactor design for the reacting system based on the characteristics of ten different
types of industrial catalytic gas-liquid reactors which includes catalyst particle diameter and loading
diffusivities flow regimes gas-liquid and liquid-solid mass transfer rates gas and liquid dispersions
heat transfer holdup among others The program solves the conservation equations and it has
checks for the validity of the design eg not allowing a complete catalyst wetting factor if the liquid
flow rate is not sufficient
Pinch Analysis Pinch technology determines the minimum utilities for heat exchanger
networks It employs three concepts the composite curves the grid diagram of process streams and
3
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
distributed control system for this purpose This data is used to update and adjust parameters in the
plant model to eliminate any plant and model mismatch Before this can be done the sampled data
has to be processed through gross error detection procedures to eliminate erroneous information that
could come from sources such as a broken instrument Then it is processed through data
reconciliation procedures to adjust it for consistency with material and energy balances This
reconciled data is precise and consistent data which is used to update the plant model parameters to
ensure the plant model accurately predicts the performance of the plant The parameters of the
economics model are updated also and these include sales prices and demand for products and costs
and availability of raw materials Typically the optimization cycle is repeated every three to twelve
hours and this interval depends on the settling time of the plant
Chemical Reactor Analysis A comprehensive interactive computer simulation for three-
phase catalatic gas-liquid reactors and subsets of these reactors which has a wide range of
applications such as oxidation hydrogenation hydrodesulfurization hydrocracking and Fischer-
Tropsch synthesis (Saleh Hopper and Walker 1995) The program interactively guides the engineer
to select the best reactor design for the reacting system based on the characteristics of ten different
types of industrial catalytic gas-liquid reactors which includes catalyst particle diameter and loading
diffusivities flow regimes gas-liquid and liquid-solid mass transfer rates gas and liquid dispersions
heat transfer holdup among others The program solves the conservation equations and it has
checks for the validity of the design eg not allowing a complete catalyst wetting factor if the liquid
flow rate is not sufficient
Pinch Analysis Pinch technology determines the minimum utilities for heat exchanger
networks It employs three concepts the composite curves the grid diagram of process streams and
3
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
the pinch point and these are applied to minimize energy use in the process The composite curves
are plots of temperature as a function of enthalpy from the material and energy balances for the
streams that need to be heated called cold streams and those that need to be cooled called hot
streams From the composite curves of the hot and cold streams the potential for energy exchange
between the hot and cold streams can be determined as well as the process requirements for external
heating and cooling from utilities such as steam and cooling water At one or more points the curves
for the hot and cold streams may come very close the process pinch and this means there is no
surplus heat for use at lower temperatures The grid diagram has vertical lines to represent the hot
and cold streams with lengths corresponding to the temperature range with the hot streams going
from top left and the cold streams from bottom right With this arrangement the heat recovery
network for the process design can be determined A grand composite temperature-enthalpy curve
can be assembled from the composite curves and the grid diagram to help select utilities and
appropriately place boilers turbines distillation columns evaporators and furnaces Also the heat
transfer surface area can be determined with the corresponding capital cost for both energy and cost
minimization
Pollution Assessment The pollution assessment module is based on the Waste Reduction
Algorithm and the Environmental Impact Theory (Cabezas et al 1997) The WAR algorithm is
based on the generic pollution balance of a process flow diagram
Pollution Accumulation = Pollution Inputs + Pollution Generation - Pollution Output (1)
It defines a quantity called as the Pollution Index to measure the waste generation in the
process This pollution index is defined as
I = wastesproducts = - (GOut + GFugitive) GPn (2)
4
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
This index is used to identify streams and parts of processes to be modified Also it allows
comparison of pollution production of different processes The WAR algorithm can be used to
minimize waste in the design of new processes as well as modification of existing processes Also
the Environmental Impact Theory (Cabezas et al 1997) is a generalization of the WAR algorithm
It describes the methodology for evaluating potential environmental impacts and it can be used in
the design and modification of chemical processes The environmental impacts of a chemical process
are generally caused by the energy and material that the process takes from and emits to the
environment The potential environmental impact is a conceptual quantity that cannot be measured
but it can be calculated from related measurable quantities
CHEMICAL COMPLEX (MULTI-PLANT) ANALYSIS SYSTEM
New methodology has been developed that determines the best configuration of plants in a
chemical complex based on economic energy environmental and sustainable costs The system
structure is shown in Figure 3 This integrated system incorporates a flowsheeting component as
shown in Figure 3 where simulations of the plants in the complex are entered Each simulation
includes the process or block flow
diagram with material and energy
balances rates equations equilibrium
relations and thermodynamic and
transports properties for the process
units and heat exchanger networks
These equations are entered through
windows and stored in the database to
5
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
be shared with the other components of the system
The objective function is entered as an equation associated with each process with related
information for prices and economic energy environmental and sustainable costs that are used in
the evaluation of the Total Cost Assessment (TCA) for the complex The TCA includes the total
profit for the complex that is a function of the economic energy environmental and sustainable
costs and income from sales of products Then the information is provided to the mixed integer
nonlinear programming solver GAMS to determine the optimum configuration of plants in the
complex Also sources of pollutant generation are located by the pollution index component of the
system using the EPA pollution index methodology (Cabezas et al 1997)
All interactions with the system are through the graphical user interface that is written in
Visual Basic As the process flow diagram for the complex is prepared equations for the process
units and variables for the streams connecting the process units are entered and stored in the
database using interactive data forms as shown on the left side in Figure 3 Material and energy
balances rate equations and equilibrium relations for the plants are entered as equality constraints
using the format of the GAMS programming language that is similar to Fortran Process unit
capacities availability of raw materials and demand for product are entered as inequality constraints
Features for developing flowsheets include adding changing and deleting the equations that describe
units and streams and their properties Usual Windows features include cut copy paste delete
print zoom reload update and grid among others A detailed description is provided in a userrsquos
manual
The system has the TCA component prepare the assessment model for use with
determination of the optimum complex configuration Economic costs are estimated by standard
6
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
methods Environmental costs are estimated from the data provided by Amoco DuPont and
Novartis in the AIChECWRT TCA report (Constable et al 1999) Sustainable costs are estimated
from the air pollution data in the AIChECWRT TCA report Improving the estimates is an on-going
effort
Industry Collaboration The system is being developed in collaboration with engineering
groups at Monsanto Enviro Chem Motiva Enterprises IMC Agrico and Kaiser Aluminum and
Chemicals to ensure it meets the needs of the chemical and petroleum refining industries The
System incorporates TCA methodology in a program from the AIChECWRT Total Cost
Assessment Methodology (Constable 1999) which provides the criteria for the best economic-
environmental design
Validation - Application to Two Chemical Complexes The system has been validated
by application to two chemical complexes In the first one the system was applied to expanding
production of sulfuric and phosphoric acid capacities and to evaluating heat recovery options at a
major chemical company and the results were compared to the companyrsquos case study A second
application of the system was based on an agricultural chemical complex with ten multiple plant
production units as found in the Baton Rouge- New Orleans Mississippi river corridor The optimal
configuration of units was determined based on economic environmental and sustainable costs A
comparison of current configuration with the optimal one was made and sensitivity to cost and
prices was analyzed
References
Chen X T A Hertwig R W Pike and J R Hopper 1998 ldquoOptimal Implementation of On-Line Optimizationrdquo Computers and Chemical Engineering Vol 22 p S435-S442
Constable D et al 1999 Total Cost Assessment Methodology Internal Managerial
7
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8
Decision Making Tool AIChECWRT AIChE 3 Park Avenue New York NY February 10 2000
Knopf F C 1993 THEN Users Manual Louisiana State University Baton Rouge LA 70803
Saleh J M J R Hopper and R E Walker 1995 Three-Phase Catalytic Gas-Liquid Reactors An Interactive Simulator Paper No 73d 1995 Spring National Meeting American Institute of Chemical Engineers Houston Texas
8